Cryo-Field Emission Scanning Electron Microscopy Imaging of a Rigid Surfactant Mesophase

Tan, Grace; Xu, Peng; John, Vijay T.; He, Jibao; McPherson, Gary L.; Agarwal, Vivek; Bose, Arijit

doi:10.1021/la801645x

Cited by 20 publications

(9 citation statements)

References 26 publications

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“…To more quantitatively analyze these micrometre-sized assembled morphologies under aqueous conditions, cryo-SEM was employed; cryo-SEM can cover larger length scales (up to several micrometres) with high resolution to tens of nanometres. 45–47 The cryo-SEM images (Fig. 2 and 3) clearly revealed the spherical morphologies formed at temperatures above the LCST of the triblock hybrid.…”

Section: Resultsmentioning

confidence: 93%

Morphological transformations in a dually thermoresponsive coil–rod–coil bioconjugate

et al. 2012

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We report the conformational and assembly behavior of a thermoresponsive triblock biohybrid conjugate under aqueous conditions. The triblock comprises of poly(diethylene glycol methyl ether methacrylate) (PDEGMEMA) conjugated to the ends of a triple-helix forming collagen-like peptide. The circular dichroism (CD) experiment confirms the ability of the collagen-like peptide middle block to assemble as a triple helix in the hybrid conjugate. Above the LCST (~35 °C), the collapse of the thermoresponsive PDEGMEMA polymer at the ends of the peptide domain resulted in a concomitant increase in the conformational stability of the peptide domain towards thermal denaturation. Upon cooling back, the kinetic conformational refolding behavior was still observed for the peptide domain in the hybrid conjugate. Static light scattering (SLS) experiments suggested the formation of supramolecular structures upon increasing solution temperatures to above the LCST. The scattering intensity increased with increasing temperature, until at 75 °C then it was found to decrease. Cryogenic scanning electron microscopy and regular transmission electron microscopy suggested the formation of spherical aggregates that increased in size with increasing temperature up to 65 °C and a morphological transformation into fibrils was also observed at 75 °C. The synergistic effect of dual thermoresponsive behavior from the peptide and the polymer block in the triblock hybrid is suggested for the observed conformational and assembly behaviors.

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Section: Resultsmentioning

confidence: 93%

Morphological transformations in a dually thermoresponsive coil–rod–coil bioconjugate

et al. 2012

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“…Analysis was performed as previously described (Tan et al 2008 ). Briefly, samples were deposited on a silicon surface and snap frozen in liquid nitrogen to ensure the conformational stability of the liquid crystals.…”

Section: Methodsmentioning

confidence: 99%

Liquid crystal delivery of ciprofloxacin to treat infections of the female reproductive tract

Pisano

Giustiniani

Francis

et al. 2019

Biomed Microdevices

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Infections of the female reproductive tract are a major cause of morbidity and mortality in humans, requiring significant investment to sustain treatment and representing a major challenge to health. The increasing prevalence of bacterial resistance, and an almost complete absence of new antibiotic therapies for the past five decades, mean there is a desperate need for novel approaches to the treatment of bacterial infections. Within the present study, we demonstrate the effective ex vivo treatment of bacterial infection of the female reproductive tract using a controlled-release, liquid crystal-based platform. Liquid crystal encapsulation of ciprofloxacin significantly enhanced its bactericidal efficacy and reduced cell toxicity. Liquid crystal structures are low-cost, simple to manufacture and provide a sustained-release profile of encapsulated ciprofloxacin. Treatment of Escherichia coli infected reproductive tract epithelial cells and whole organ cultures with liquid crystal encapsulated ciprofloxacin proved to be an effective strategy for reducing bacterial load and reproductive tract inflammatory responses to infection. These data suggest that such an approach could provide an efficacious treatment modality for enhancing the effectiveness of current antibiotic therapies. Electronic supplementary material The online version of this article (10.1007/s10544-019-0385-x) contains supplementary material, which is available to authorized users.

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“…Cryogenic-transmission electron microscopy (cryo-TEM) is another microscopy technique that can be used to study the structural morphology of lipid mesophases. The general size of the particles and their internal structure can be observed on a local scale with resolutions down to 1.8 Å (Tan et al, 2008;Fong et al, 2012;Merk et al, 2016). This technique involves pipetting the dispersed material onto a copper grid perforated with carbon films that have been prepared under glow discharge in nitrogen.…”

Section: Electron Microscopymentioning

confidence: 99%

Formation of Self-Assembled Mesophases During Lipid Digestion

Pham¹,

Clulow²

2021

Front. Cell Dev. Biol.

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Lipids play an important role in regulating bodily functions and providing a source of energy. Lipids enter the body primarily in the form of triglycerides in our diet. The gastrointestinal digestion of certain types of lipids has been shown to promote the self-assembly of lipid digestion products into highly ordered colloidal structures. The formation of these ordered colloidal structures, which often possess well-recognized liquid crystalline morphologies (or “mesophases”), is currently understood to impact the way nutrients are transported in the gut and absorbed. The formation of these liquid crystalline structures has also been of interest within the field of drug delivery, as it enables the encapsulation or solubilization of poorly water-soluble drugs in the aqueous environment of the gut enabling a means of absorption. This review summarizes the evidence for structure formation during the digestion of different lipid systems associated with foods, the techniques used to characterize them and provides areas of focus for advancing our understanding of this emerging field.

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Cryo-Field Emission Scanning Electron Microscopy Imaging of a Rigid Surfactant Mesophase

Cited by 20 publications

References 26 publications

Morphological transformations in a dually thermoresponsive coil–rod–coil bioconjugate

Morphological transformations in a dually thermoresponsive coil–rod–coil bioconjugate

Liquid crystal delivery of ciprofloxacin to treat infections of the female reproductive tract

Formation of Self-Assembled Mesophases During Lipid Digestion

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